Slipping property imparting agent for clear coating and clear coating paper having the agent applied thereon

ABSTRACT

Produce a slipping property imparting agent for clear coat that reduces scum production: wherein, (1) the agent comprises a copolymer whose constituents are unsaturated olefin (constituent (a)) and unsaturated carboxylic acid (carboxylate) (constituent (b)); (2) constituent (a) accounts for 50 to 99 mol percent and constituent (b) accounts for 50 to 1 mol percent, respectively, of the total mol number of constituents (a) and (b) combined; and (3) a constituent (c) that can be polymerized with the constituents (a) and (b) is contained, as necessary, by up to 20 mol percent of the total mol number of constituents (a) and (b) combined.

FIELD OF THE INVENTION

This invention relates to a slipping property imparting agent for clearcoat and a clear coated paper processed therewith.

To be specific, this invention relates to a slipping property impartingagent for clear coat that can gradually reduce the friction coefficientof a printing paper when applied over the paper surface in a sizingpress or calender or using a spray applicator, as well as a coated paperprocessed with said slipping property imparting agent.

BACKGROUND OF THE INVENTION

A number of slipping property imparting agents for coating are presentlyknown, including higher fatty-acid metal salt, higher fatty-acid amide,wax emulsion, polyethylene glycol, polyethylene glycol ester, liquidhydrocarbon oil emulsion, polyethylene dispersion and sulfurized fattyoil (Japanese Patent Application Laid-open No. 3-137295 and JapanesePatent Application Laid-open No. 58-8200). These slipping propertyimparting agents can be used in pigment coating materials of pH7 orhigher that contain calcium carbonate. However, in clear coatingmaterials of lower than pH7 whose main constituent is starch, theseslipping property imparting agents have heretofore failed to satisfy therequired slippage for clear coat, because they produce an agglutinatedproduct called scum if the dispersion stability drops and a shearingload is applied during the coating process.

Against the backdrop of increasing use of recycled paper in paperproduction, the market is witnessing lower blending ratios of mechanicalpulps or extracts from mechanical pulps. In addition, calcium carbonatefillers are being used to produce papers having a neutral pH level. As aresult, the friction coefficient of printing paper is increasing ingeneral. A higher friction coefficient of printing paper can lead towrinkling or other problems during web offset printing that affect asmooth traveling of paper through the cylinders. Therefore, it isimportant to adjust the friction coefficient of paper to an optimallevel in accordance with the specific operation of each printing plant.

To reduce the friction coefficient of paper, alkylketene dimer (AKD) ortalc can be added to the material during the paper production process,or a slipping property imparting agent for pigment coat can be coated onthe produced paper. If AKD is added to the paper material, in summertimeAKD may migrate on the take-up roller, thereby causing the frictioncoefficient to decrease significantly on the top roller and consequentlyallowing the paper to slip during printing. When talc is added to thepaper material, the blending ratios of white carbon filler, calciumcarbonate filler or other fillers having a high specific scatteringcoefficient must be reduced, which inevitably reduces the opacity ofpaper. Therefore, these methods are not suitable in the production ofhigh-quality papers. In addition, applying a clear pigment coatcontaining slipping property imparting agents can produce anagglutinated product called scum, if the dispersion stability drops anda shearing load is applied during the coating process, which can cause amajor problem on the printing line.

The aim of the present invention is to provide a slipping propertyimparting agent for clear coat that reduces scum production even whenthe dispersion stability drops and a shearing load is applied during thecoating process.

SUMMARY OF THE INVENTION

The inventors have carried out extensive studies in order to solve theaforementioned problems by way of providing a new slipping propertyimparting agent for clear coat that reduces scum production, and havefound that a slipping property imparting agent for clear coat thatcontains a copolymer whose constituents are unsaturated olefin andunsaturated carboxylic acid (carboxylate) and/or a neutralized salt oftheir carboxyl groups will produce no scum, and that this slippingproperty imparting agent will gradually reduce the dynamic frictioncoefficient of a base printing paper and therefore will not affectprintability when coated on the paper to a coating weight of 0.001 to 1g/m² by solid content.

In other words, the present invention is basically characterized asfollows:

(1) A slipping property imparting agent for clear coat which comprises acopolymer whose constituents are unsaturated olefin and unsaturatedcarboxylic acid (carboxylate).

(2) A slipping property imparting agent for clear coat as described in(1) above, wherein the aforementioned copolymer comprising unsaturatedolefin (constituent (a)) and unsaturated carboxylic acid (carboxylate)(constituent (b)) contains 50 to 99 mol percent of constituent (a) and50 to 1 mol percent of constituent (b) to the total mol number ofconstituents (a) and (b) combined.

(3) A slipping property imparting agent for clear coat as described in(1) or (2) above, wherein the aforementioned copolymer contains aconstituent (constituent (c)) that can be copolymerized with theaforementioned unsaturated olefin (constituent (a)) and unsaturatedcarboxylic acid (carboxylate) (constituent (b)), by up to 20 mol percentof the total mol number of constituents (a) and (b) combined.

(4) A slipping property imparting agent for clear coat as described inany of (1) though (3) above, wherein the aforementioned copolymercontains 0.05 to 3 mol equivalent of alkalis per 1 mol equivalent ofcarboxyl groups.

(5) A slipping property imparting agent for clear coat as described inany of (1) though (4) above, wherein the cumulative average particlesize of the aforementioned copolymer is 1 to 50,000 nm.

(6) A clear coated paper coated with 0.001 to 1 g/m² by solid content ofthe slipping property imparting agent for clear coat as described in anyof (1) though (5) above.

BEST MODE FOR CARRYING OUT THE INVENTION

The copolymer proposed by the present invention for use in a slippingproperty imparting agent for clear coat that reduces scum production, isa copolymer containing unsaturated olefin (constituent (a)) andunsaturated carboxylic acid (carboxylate) (constituent (b)).

Examples of the unsaturated olefin (constituent (a)) that constitutesthe copolymer used in the present invention may be any one or more ofthe following: olefin derivatives such as ethylene, propene,cyclopropene, 1-fluoropropene, 2-fluoropropene, 3-fluoropropene,1,1,1-trifluoropropene, hexafluoropropene, aryl alcohol, 1-butene,2-butene, isobutene, cyclobutene, methylene cyclopropane,hexafluorocyclobutene, 1-pentene, 2-pentene, 2-methyl-1-butene,3-methyl-1-butene, 2-methyl-2-butene, cyclopentene,1-methyl-cyclobutene, 3-methyl-cyclobutene, methylene cyclobutane, vinylcyclopropane, 1-fluorocyclopentene, 1-hexene, 2-hexene, 3-hexene,2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene,2-methyl-2-pentene, 3-methyl-2-pentene, 4-methyl-2-pentene,2-ethyl-1-butene, 2,3-dimethyl-1-butene, 3,3-dimethyl-1-butene,2,3-dimethyl-2-butene, 3,3-dimethyl-1-butene, 2,3-dimethyl-2-butene,cyclohexene, 1-methyl cyclopentene, 3-methyl cyclopentene, 4-methylcyclopentene, methylene cyclopentane, isopropenyl cyclopropane,1-fluorocyclohexene, 1-heptene, 2-heptene, 3-heptene, 2-methyl-1-hexene,3-methyl-1-hexene, 4-methyl-1-hexene, 5-methyl-1-hexene,2-methyl-2-hexene, 3-methyl-2-hexene, 4-methyl-2-hexene,5-methyl-2-hexene, 2-methyl-3-hexene, 2,3-dimethyl-1-pentene,2,4-dimethyl-1-pentene, 3,3-dimethyl-1-pentene, 3,4-dimethyl-1-pentene,4,4-dimethyl-1-pentene, 2,3-dimethyl-2-pentene, 2,4-dimethyl-2-pentene,3,3-dimethyl-2-pentene, 3,4-dimethyl-2-pentene, 4,4-dimethyl-2-pentene,cycloheptene, 1-methyl cyclohexene, 3-methyl cyclohexene, methylenecyclohexane, 2-cyclopropyl-1-butene, 2-cyclopropyl-2-butene,1-fluorocycloheptene, 1-octene, 2-octene, 3-octene, 4-octene,2-methyl-1-heptene, 6-methyl-1-heptene, 3-methyl-2-heptene,4-methyl-2-heptene, 2,3-dimethyl-2-hexene, 2,3,3-trimethyl-1-pentene,2,4,4-trimethyl-1-pentene, 2,3,4-trimethyl-2-pentene,2,4,4-trimethyl-2-pentene, 3,4,4-trimethyl-2-pentene, cyclooctene,1-methyl cycloheptene, 5-methyl cycloheptene, 1,1-dimethyl cyclohexene,1,2-dimethyl cyclohexene, 1,3-dimethyl cyclohexene, 1,4-dimethylcyclohexene, 1,5-dimethyl cyclohexene, 3,5-dimethyl cyclohexene,3,6-dimethyl cyclohexene, 1,2,3-trimethyl cyclopentene, vinylcyclohexane, 2-cyclopropyl-1-pentene, 2-cyclopropyl-2-pentene,2-cyclopropyl-3-methyl-1-butene, 1,1,1-trifluoro-2-octene, 1-nonene,2-nonene, 3-nonene, 4-nonene, 2,6-dimethyl-2-heptene,2,2,5-trimethyl-3-hexene, 2,4,5-trimethyl-2-hexene, 1,2,3-trimethylcyclohexene, 1,3,5-trimethyl cyclohexene, 1,4,4-trimethyl cyclohexene,1,4,5-trimethyl cyclohexene, 1,5,5-trimethyl cyclohexene,1,5,6-trimethyl cyclohexene, 1,6,6-trimethyl cyclohexene, 2-methylvinylcyclohexane, 3-methylvinyl cyclohexane, 4-methylvinyl cyclohexane,2-cyclopropyl-1-hexene, 2-cyclopropyl-2-hexene, 3-phenyl-1-propene,1-decene, 2-decene, 4-decene, 5-decene, 1,4,4-trimethyl cycloheptene,1-isopropyl-2-methyl cyclohexene, 1-isopropyl-4-methyl cyclohexene,1-isopropyl-5-methyl cyclohexene, 4-isopropyl-1-methyl cyclohexene,5-isopropyl-3-methyl cyclohexene, 1-isopropenyl-4-methyl cyclohexane,α-pinene, β-pinene, 4-phenyl-1-butene, 5-phenyl-1-butene, 1-dodecene,3-phenyl-1-pentene, 5-phenyl-1-pentene, 1-phenyl-2-pentene,5-phenyl-2-pentene, 6-phenyl-1-hexene, 1-phenyl-2-hexene,1-phenyl-3-hexene, 2-phenyl-3-hexene, 1-phenyl cyclohexene, 3-phenylcyclohexene, 4-phenyl cyclohexene, norbornene and 5-methyl norbornene;styrene derivatives such as styrene, a-methyl styrene, chlorostyrene,cyanostyrene, aminostyrene and hydroxystyrene; and diene derivativessuch as butadiene, isoprene and allene. Of these, ethylene and styreneprovide a suitable unsaturated olefin for the purpose of the presentinvention.

The unsaturated carboxylic acid (carboxylate) (constituent (b)) thatconstitutes the copolymer used in the present invention may be any oneor more of the following: acrylic acid derivatives such as acrylic acid,acrolein, crotonic acid, isocrotonic acid, 2-ethyl acrylic acid,3,3-dimethyl acrylic acid, 3-propyl acrylic acid, 3-isopropyl acrylicacid, 2-isopropyl acrylic acid, trimethyl acrylic acid, 3-butyl acrylicacid, 2-butyl acrylic acid, 2-methyl-2-hexenoic acid, 3-methyl-3-propylacrylic acid, 2,3-diethyl acrylic acid, 4-methyl-2 hexanoic acid,3,3-diethyl acrylic acid, 2,3-dimethyl-3-ethyl acrylic acid,3,3-dimethyl-2-ethyl acrylic acid, 3-methyl-3-isopropyl acrylic acid,2-methyl-3-isopropyl acrylic acid, 2-octenoic acid, 2-pentyl acrylicacid, 2-butyl crotonic acid, 2-ethyl-3-propypl acrylic acid,4-ethyl-2-hexenoic acid, 2-methyl-3,3-diethyl acrylic acid, 2-nonenoicacid, 2-hexyl acrylic acid, 2-methyl-3-pentyl acrylic acid,3-methyl-3-pentyl acrylic acid, 3,3-dipropyl acrylic acid,3-methyl-2-ethyl-2-hexenoic acid, 2-decenoic acid, 3-methyl-3-hexylacrylic acid, nonene-4-carboxylic acid and 4-ethyl-2-octenoic acid;methacrylic acid derivatives such as methacrylic acid, methacrolein,methacryl isocyanate, methacryl isothiocyanate and methacryl fluoride;maleic anhydride derivatives such as maleic anhydride, methyl maleicanhydride, dimethyl maleic anhydride, phenyl maleic anhydride and fluoromaleic anhydride; maleic acid derivatives such as maleic acid, methylmaleic acid, dimethyl maleic acid, phenyl maleic acid, fluoro maleicacid; monohydroxyl compounds of maleic acid/maleic anhydride andmethanol, ethanol, propanol, butanol, hexanol, octanol, dodecanol oroctadecanol; partial esterified compounds such as ethylcellosolve andbutylcellosolve; dicarboxylic acids such as oxalic acid, malonic acid,succinic acid, itaconic acid, fumaric acid, glutaric acid, adipic acid,galactaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid,undecanoic diacid, dodecanoic diacid, tridecanoic diacid, tetradecanoicdiacid, pentadecanoic diacid, hexadecanoic diacid, heptadecanoic diacid,octadecanoic diacid, nonadecanoic diacid, eicosanoic diacid, docosanoicdiacid, phthalic acid, isophthalic acid and telephthalic acid; andpartially or completely neutralized salts thereof. Of these, acrylicacid, methacrylic acid, maleic acid and maleic anhydride or theirpartially or completely neutralized salts provide a suitable unsaturatedcarboxylic acid (carboxylate) for the purpose of the present invention.

The content of unsaturated olefin (constituent (a)) in the copolymershould be normally 50 to 99 mol percent, or preferably 60 to 98 percent,or at best 70 to 97 mol percent. If the content of unsaturated olefin inthe copolymer is less than 50 mol percent, the manifested slippage willdecrease. On the other hand, if the content of unsaturated olefin in thecopolymer exceeds 99 mol percent, the mechanical stability of theslipping property imparting agent will decrease and therefore anagglutinated product called scum will be produced if a shearing load isapplied during the coating process, which can cause a major problem onthe printing line. This is not desirable.

The content of unsaturated carboxylic acid (carboxylate) (constituent(b)) in the copolymer that provides the slipping property impartingagent proposed by the present invention should be normally 1 to 50 molpercent, or preferably 2 to 40 percent, or at best 3 to 30 mol percent.If the content of unsaturated carboxylic acid (carboxylate) in thecopolymer is less than 1 mol percent, and the pH value of the coatingmaterial is less than 7, the dispersion stability of the slippingproperty imparting agent in the coating material will decrease, and themechanical stability will also drop. As a result, an agglutinatedproduct called scum will be produced if a shearing load is appliedduring the coating process, which can cause a major problem on theprinting line. This is not desirable. On the other hand, if the contentof unsaturated carboxylic acid (carboxylate) in the copolymer exceeds 50mol percent, the manifested slippage will decrease and the tackinesswill increase, which is also not desirable.

In other words, in the copolymer containing unsaturated olefin(constituent (a)) and unsaturated carboxylic acid (carboxylate)(constituent (b)), it is preferable to adjust the content of constituent(a) to 50 to 99 mol percent and that of constituent (b) to 50 to 1 molpercent relative to the total mol number of constituents (a) and (b)combined, from the viewpoint of increasing the manifested slippage,improving the mechanical stability and reducing the tackiness.

The copolymer may contain a constituent that can be copolymerized withthe aforementioned unsaturated olefin (constituent (a)) and unsaturatedcarboxylic acid (carboxylate) (constituent (b)). This constituent isreferred to as constituent (c). Constituent (c) may be any one or moreof the following: vinyl esters such as vinyl acetate and vinylpropionate; unsaturated alkyl ester carboxylates such as methyl esteracrylate, ethyl ester acrylate, propyl ester acrylate, butyl esteracrylate, isooctyl ester acrylate, 2-ethylhexyl ester acrylate, methylester methacrylate, ethyl ester methacrylate, propyl ester methacrylate,butyl ester methacrylate, isooctyl ester methacrylate, 2-ethylhexylester acrylate, dimethyl ester maleate and diethyl ester maleate;polyoxyalkylenes such as polyoxyethylene (ethylene oxide added by 2 to100 in mols) monoester acrylate, polyoxyethylene propylene (alkyleneoxide added by 2 to 100 mols) monoester acrylate, polyoxyethylenepropylene (propylene oxide added by 2 to 100 mols) monoester acrylate,polyoxyethylene (ethylene oxide added by 2 to 100 mols) monoestermethacrylate, polyoxyethylene propylene (alkylene oxide added by 2 to100 mols) monoester methacrylate, and polyoxyethylene propylene(propylene oxide added by 2 to 100 mols) monoester methacrylate;alkoxypolyalkylene glycol ester acrylates such as methoxypolyalkyleneglycol (alkylene oxide added by 2 to 100 mols) ester acrylate,ethoxypolyalkylene glycol (alkylene oxide added by 2 to 100 mols) esteracrylate, propoxypolyalkylene glycol (alkylene oxide added by 2 to 100mols) ester acrylate, butoxypolyalkylene glycol (alkylene oxide added by2 to 100 mols) ester acrylate, methoxypolyalkylene glycol (alkyleneoxide added by 2 to 100 mols) ester methacrylate, ethoxypolyalkyleneglycol (alkylene oxide added by 2 to 100 mols) ester methacrylate,propoxypolyalkylene glycol (alkylene oxide added by 2 to 100 mols) estermethacrylate and butoxypolyalkylene glycol (alkylene oxide added by 2 to100 mols) ester methacrylate; polyoxyalkylene monovinyl ethers such aspolyoxyethylene (ethylene oxide added by 2 to 100 mols) monovinyl ether,polyoxyethylene propylene (alkylene oxide added by 2 to 100 mols)monovinyl ether, and polyoxypropylene (propylene oxide added by 2 to 100mols) monovinyl ether; alkoxyalkylene glycol mononvinyl ethers such asetoxypolyalkylene glycol (alkylene oxide added by 2 to 100 mols)monovinyl ether, propoxypolyalkylene glycol (alkylene oxide added by 2to 100 mols) monovinyl ether and butoxypolyalkylene glycol (alkyleneoxide added by 2 to 100 mols) monovinyl ether; polyoxyalkylene arylethers such as polyoxyethylene (ethylene oxide added by 2 to 100 mols)aryl ether, polyoxyethylene propylene (alkylene oxide added by 2 to 100mols) aryl ether and polyoxypropylene (propylene oxide added by 2 to 100mols) aryl ether; alcoxypolyalkylene glycol aryl ethers such asmethoxypolyalkylene glycol (alkylene oxide added by 2 to 100 mols) arylether, ethoxypolyalkylene glycol (alkylene oxide added by 2 to 100 mols)aryl ether, propoxypolyalkylene glycol (alkylene oxide added by 2 to 100mols) aryl ether and butoxypolyalkylene glycol (alkylene oxide added by2 to 100 mols) aryl ether; hydroxyl alkyl acrylates such ashydroxymethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate,hydroxybutyl acrylate, hydroxymethyl methacrylate, hydroxyethylmethacrylate, hydroxypropyl methacrylate and hydroxybutyl methacrylate;amide compounds such as acrylamide, N′,N′-dimethyl acrylamide, N-alkanolacrylamide, methacrylamide and N-alkanol methacrylamide; and dimethylaminomethyl acrylate, dimethyl aminoethyl acrylate, diethyl aminomethylacrylate, diethyl aminoethyl acrylate, dimethyl aminomethylmethacrylate, dimethyl aminoethyl methacrylate, diethyl aminomethylmethacrylate, diethyl aminoethyl methacrylate, vinyl chloride, benzilacrylate, benzil methacrylate, styrene sulfonate, vinyl sulfonate,2-acrylamide-2-methylpropane sulfonate and vinyl pyridine.

Constituent (c) in the copolymer may account for up to 20 mol percent ofthe total mol number of constituents (a) and (b) combined. If thecontent of constituent (c) in the copolymer exceeds 20 mol percent, themanifested slippage will decrease or the mechanical stability of theslipping property imparting agent will drop. As a result, anagglutinated product called scum will be produced if a shearing load isapplied during the coating process, which can cause a major problem onthe printing line. This is not desirable.

The copolymer used in the present invention can be obtained bycopolymerizing the constituent unsaturated polyolefin (a), constituentunsaturated carboxylic acid (carboxylate) (b) and constituent (c) usingthe high-pressure radical polymerization method, radical polymerizationmethod or other known polymerization methods (U.S. Pat. No. 3,239,370,U.S. Pat. No. 3,520,861, Canada Patent No. 655298, U.S. Pat. No.3,658,741, U.S. Pat. No. 3,884,857, U.S. Pat. No. 3,988,509, U.S. Pat.No. 4,248,990, U.S. Pat. No. 4,252,924, etc.) The present inventionallows for addition of alkalis to the slipping property imparting agentfor clear coat. At this time, the copolymer may be a neutralized saltcomprising partially or completely neutralized carboxyl groups.

The content of alkalis should be normally 0.05 to 3 mol equivalent, orpreferably 0.2 to 2 mol equivalent, or at best 0.3 to 1.5 mol equivalentper 1 mol equivalent of carboxyl groups in the copolymer. If the contentof alkalis is less than 0.05 mol equivalent, a favorable water-baseddispersion cannot be obtained. On the other hand, if the content ofalkalis exceeds 3 mol equivalent, a favorable water-based dispersioncannot be obtained due to gelatinization, and also the printing papercoated with said water-based dispersion will have a lower waterresistance. This is not desirable.

Examples of alkalis that can be used to neutralize the copolymer includethe following: ammonia; amine compounds such as alkylamines(monoethylamine, monobutylamine, dibutylamine, tributylamine, etc.),alkanolamines (monoethanolamine, diethanolamine, triethanolamine, etc.),ethylene diamine and polyethylene polyamines (diethylene triamine,triethylene tetramine, etc.), polyoxyalkylene alkylamines(polyoxyethylene laurylamine, polyoxylene tallowamine, polyoxyethylenestearylamine, polyoxyethylene oleylamine, polyoxyethylene tallowpropylene diamine and polyoxyethylene stearyl propylene diamine, etc.);and salts of metals in the first group of the periodic system (lithium,sodium, potassium, etc.), second group of the periodic system(magnesium, calcium, zinc, etc.), third group of the periodic system(aluminum, etc.), and eighth group of the periodic system (ferrous,cobalt, nickel, etc.) Of these alkalis, ammonium, monoethanolamine,diethanolamine and triethanolamine, as well as lithium, sodium,potassium, magnesium, calcium and zinc salts are preferred. Thesealkalis can be used alone or in any combination.

The cumulative volume-average particle size of the copolymer (50 percentvolume-average particle size measured on a laser-diffraction typeparticle-size distribution measuring machine) should be normally 1 to50,000 nm, or preferably 1 to 10,000 nm, or at best 5 to 5,000 nm. Ifthe cumulative volume-average particle size is less than 1 nm, themanifested slippage will decrease. On the other hand, if cumulativevolume-average particle size exceeds 50,000 nm, not only the smoothnessof the printing paper will decrease, but the manifested slippage perunit weight of slippage-agent added will also decrease. This is notdesirable.

The shape of the copolymer particle is not specified, and slippage willmanifest as long as copolymer particles exist on the paper surface.Examples of particle shapes include spherical, fusiform, bar-like,angular, columnar, needle-like, platy and amorphous. Among these,spherical and amorphous particles are preferred.

The number-average molecular weight of the copolymer should be normally500 to 50,000, or preferably 800 to 30,000, or at best 1,000 to 20,000.If the number-average molecular weight is less than 500 or exceeds50,000, the manifested slippage will decrease. This is not desirable.

The coating weight of the slipping property imparting agent provided bythe present invention can be increased or decreased as necessary inaccordance with the purpose of application. However, generally a coatingweight of 0.001 to 1 g/m² by solid content is preferred.

The copolymer used in the slipping property imparting agent proposed bythe present invention is applied in a water-based dispersion. The solidcontent concentration of the copolymer in the water-based dispersionshould be normally 1 to 80 mass percent, or preferably 5 to 60 masspercent, or at best 10 to 50 mass percent. If the concentration of thecopolymer is less than 1 mass percent, a large amount must be added tothe coating solution to achieve sufficient slippage. On the other hand,if the concentration of the copolymer exceeds 80 mass percent, theviscosity of the dispersion will increase and the dispersion will becomedifficult to handle.

A water-based dispersion of the neutralized salt of the copolymer can beeasily produced by any of the following methods: [1] place water, thecopolymer and alkalis into a reaction container, heat the mixture to themelting point of the copolymer or above, emulsify and disperse thecopolymer using an agitating mixer or disperser, and then let theobtained dispersion cool; [2] add water or hot water into a fusedmixture of the copolymer and alkalis under agitation, emulsify anddisperse the copolymer using an agitating mixer or disperser, and thenlet the obtained dispersion cool; [3] introduce a fused mixture of thecopolymer and alkalis under agitation into a water heated to the meltingpoint of the copolymer or above, emulsify and disperse the copolymerusing an agitating mixer or disperser, and then let the obtaineddispersion cool; and [4] add water under agitation to ahigh-concentration (60 percent or more) water-based dispersion of afused mixture containing the copolymer and alkalis, and then let thediluted dispersion cool. However, the production method is not limitedto the above, and the water-based dispersion may be obtained using anyemulsifying method and/or dispersion method.

The agitating mixer may be a propeller-type agitator, dissolver,homo-mixer, ball mill, sand mill, supersonic disperser, kneader, linemixer, or the like.

The disperser may be a propeller-type agitator, piston-typehigh-pressure emulsifier, homo-mixer, supersonic emulsifying disperser,pressure-nozzle type emulsifier, high-speed/high-shear rotary typeagitating disperser or colloid mill. It may also be a media-typedisperser that uses various medias such as glass beads and steel ballsto crush and disperse the target substance, such as a sand grinder,agitator mill, ball mill or atritor. Two or more of these dispersers canbe combined, or an agitating mixer may also be used in conjunction.

Surface active agents and/or water-soluble polymers may be used, so thatthe cumulative average particle size or viscosity will not changesignificantly even when the water-based dispersion of the neutralizedsalt of the copolymer is stored for a long period.

Examples of surface active agents include the following: sorbitan fattyacid ester, glycerin fatty acid ester, polyoxyethylene castor oil fattyacid ester, polyoxyethylene hardened castor oil fatty acid ester,diglycerin fatty acid ester, sucrose fatty acid ester, polyglycerinfatty acid ester, polyglycerin condensed ricinoleic acid ester,polyether modified silicone, polyoxyethylene sorbitan fatty acid ester,polyoxyethylene sorbit fatty acid ester, polyoxyethylene glycerin fattyacid ester, polyoxyethylene alkyl ether, polyoxyethylene propylene alkylether, polyoxyethylene alkyl phenyl ether, polyoxyethylene propylenealkyl phenyl ether, polyoxyethylene castor oil ether, polyoxyethylenehardened castor oil ether, polyoxyethylene alkylamine, polyoxyethylenefatty acid amide, polyoxyethylene alkyl sulfuric ester salt, higheralcohol sulfuric ester salt, alkyl ether sulfuric ester salt, sulfatedoil, sulfated fatty acid ester, sulfated olefin, alkyl benzenesulfonate, α-olefin sulfonate, alkyl sulfosuccinate, partial ester saltof polyoxyethylene alkyl ether/sulfosuccinate, polyoxyethylene alkylphenyl ether (polyoxyethylene octyl phenyl ether, polyoxyethylene nonylphenyl ether, etc.), polyoxyethylene alkyl ether (polyoxyethylenestearyl ether, polyoxyethylene grade 2 tridecyl ether, etc.),polyoxyethylene glycol fatty acid ester (polyoxyethylene glycol lauricacid ester, polyoxyethylene glycol oleic acid ester, etc.), fatty acidalkanolamide (lauric acid diethanolamide, stearic acid monoethanolamide,etc.)

Examples of salts include complete or partial salts of the following:ammonia; amine compounds such as alkylamines (monoethylamine,monobutylamine, triethylamine, etc.) and alkanolamines(monoethanolamine, diethanolamine, triethanolamine, etc.); and metals inthe first group of the periodic system (lithium, sodium, potassium,etc.) or second group of the periodic system (magnesium, calcium, zinc,etc.).

Examples of water-soluble polymers include the following: cellulose,pullulan, sodium alginate, Arabian gum, guar gum, carageenan, gelatin,curdlan, agar, starch, hyaluronic acid, scleroglucan, schizophyllan,lentinan, paramylon, callose, laminaran, glucomannan, arabinogalactan,xanthan gum, welan gum, rhamsan gum, tragacanth gum, carob gum, locustbean gum, pectin, quince seed, algae colloid, glycyrrhetinic acid,dextran, collagen, casein, albumin, agarose, glycogen, methylcellulose,ethylcellulose, nitrocellulose, carboxymethylcellulose,hydroxyethylcellulose, hydroxypropylcellulose,hydroxypropylmethylcellulose, hydroxyethylmethylcellulose, cellulosesodium sulfate, carboxymethylethylcellulose, propylene glycol alginateester, polyvinyl pyrolidone, carboxymethyl starch, methylhydroxypropylstarch, cellulose acetate phthalate, polyvinyl alcohol, polyethyleneoxide, polyoxyethylene propylene copolymer, polyacrylamide,polymethacrylamide, polyacrylic acid, polyacrylate, polymethacrylicacid, polymethacrylate, polystyrene sulfonic acid, polystyrenesulfonate, naphthalenesulfonic formalin condensate, naphthalenesulfonicformalin condensate salt, acrylamide and acrylate copolymer, acrylamideand methacrylate copolymer, methacrylamide and acrylamide copolymer,methacrylamide and methacrylic acid copolymer, methacrylamide andmethacrylate copolymer, acrylic acid and maleic acid copolymer, acrylateand maleate copolymer, styrene and maleic acid copolymer, and styreneand maleate copolymer.

Examples of salts include complete or partial salts of the following:ammonia; amine compounds such as alkylamines (monoethylamine,monobutylamine, triethylamine, etc.) and alkanolamines(monoethanolamine, diethanolamine, triethanolamine, etc.); and metals inthe first group of the periodic system (lithium, sodium, potassium,etc.) or second group of the periodic system (magnesium, calcium, zinc,etc.).

The blending ratio of surface active agents and/or water-solublepolymers should be normally 0 to 50 parts by mass, or preferably 0 to 30parts by mass, or at best 0 to 20 parts by mass, to 100 parts by mass ofthe neutralized salt of the copolymer. If the ratio of surface activeagents and/or water-soluble polymers exceeds 50 parts by mass, thecoating solution will generate more foams, thereby affecting theprinting line. Water resistance of the printing paper will also drop.

The water-based dispersion of the neutralized salt of the copolymer usedin the present invention may contain antioxidants, UV absorbents,waterproofing agents, antistatic agents, weather stabilizers, foulinginhibitors, dispersants, antiseptic agents, disinfectants, antifoamers,slipping property imparting agents, antiblocking agents, viscosityenhancers, water-retaining agents, aromatic chemicals, dyes andpigments.

As for the pulps used in the production of a paper or paperboard onwhich to apply the slipping property imparting agent for paper asproposed by the present invention, any of the following may be used:bleached or unbleached chemical pulps such as kraft pulp and sulfitepulp; groundwood pulps; bleached or unbleached high-yield pulps such asmechanical pulp and thermo-mechanical pulp; and waste-paper pulps suchas waste newspaper, waste magazine paper, waste corrugated cardboard anddeinked waste paper. The paper or paperboard before being coated withthe slipping property imparting agent for paper as proposed by thepresent invention may use any of the following additives to manifest theproperties required of each paper type: fillers; dyes; sizing agentssuch as rosin-based sizing agent for acid paper, sizing agent forneutral paper based on alkylketene dimmer or alkenyl succinic anhydride,and rosin-based sizing agent for neutral paper; dry paper-strengtheningagents; wet paper-strengthening agents; retention-improving agents,drainage-improving agents, and antifoamers. As for fillers, any one ormore of clay, talc, titanium oxide, heavy calcium carbonate andprecipitated calcium carbonate may be used.

The coating machine used to apply a clear coat containing the slippingproperty imparting agent for paper as proposed by the present inventionmay be a sizing press, film press, gate-roll coater, symsizer, bladecoater, calender, bar coater, knife coater, air-knife coater, curtaincoater, or the like.

It is also possible to use a spray coating machine to apply the clearcoat on the base paper surface.

The slipping property imparting agent for paper as proposed by thepresent invention may be applied by itself, or as a coating solutionmixing the slipping property imparting agent with any of the following:starches such as oxidized starch, phosphate esterified starch,custom-made modified starch and cationic starch; celluloses such ascarboxylic methylcellulose; and water-soluble polymers such as polyvinylalcohol, polyacrylamide and sodium alginate. It is also possible to useone or more of other additives including surface-sizing agents,antislippage agents, preservatives, rustproofing agents, antifoamers,viscosity-adjusting agents, dyes and pigments.

Various papers and paperboard can be coated with the slipping propertyimparting agent for clear coat as proposed by the present invention. Forexample, these include: recording papers such as PPC paper, inkjetpaper, laser printer paper, form paper, thermal transfer paper andthermo-sensitive recording paper; coated papers such as art paper, castcoated paper and woodfree coated paper; packaging papers such as kraftpaper and pure-white roll paper; other papers such as notepad paper,paper for making books, printing paper and newsprint paper; paperboardsfor making paper containers such as manila board paper, white paperboardand chip board paper; and other paperboards such as liner. The slippingproperty imparting agent proposed by the present invention manifestssufficient slippage when applied on a paper or paperboard, while alsoadding a sizing property to such paper or paperboard.

[Operation]

All of the conventional slipping property imparting agents for paperconsisting of higher fatty-acid metal salt, higher fatty-acid amide, waxemulsion, polyethylene glycol, polyethylene glycol ester, liquidhydrocarbon oil emulsion, polyethylene dispersion and sulfurized fattyoil have their slipping property imparting particles stabilized bysurface active agents and/or water-soluble polymers that are adsorbed tothe slipping property imparting particles. Therefore, the pH levels ofthese agents are low, and in an environment of high shearing load thecollision among slipping property imparting particles causes the surfaceactive agents and/or water-soluble polymers to separate, therebyallowing the slipping property imparting particles to agglutinate andproduce scum.

On the other hand, the neutralized salt of the copolymer proposed by thepresent invention has its anion groups covalent-bonded with the polymerchains. Therefore, despite its low pH level, the slipping propertyimparting agent maintains excellent dispersion stability even in anenvironment of high shearing load and therefore suppresses scumproduction. Although the manifested slippage will decrease when theratio of unsaturated carboxylic acid (carboxylate) (b) increases, if theratio is kept to 50 mol percent of the copolymer composition or less thedrop in manifested slippage will be kept to a minimum and the frictioncoefficient can be reduced efficiently.

EXAMPLES

The following explains the present invention in details using examples.Note that the present invention is not limited to these examples. Unlessotherwise specified, the part(s) used in the examples, test methods,etc., refers to part(s) by mass.

(1) Preparation of Slipping Property Imparting Agents

Production Example 1

All of the following constituents were placed in an autoclave andagitated using a propeller-type agitator (temperature: 150° C., period:3 hours). The obtained mixture was further processed on a high-pressurehomogenizer (pressure: 1,500 kg/cm²) and then cooled to 25° C.

The cumulative volume-average particle size of the obtained slippingproperty imparting agent (A) was 60 nm. Copolymer  25.00 parts by mass(Ethylene/acrylic acid = 90/10 [mol percent]) Potassium hydroxide  0.03part by mass Water  74.97 parts by mass Total 100.00 parts by mass

Production Example 2

All of the following constituents were placed in an autoclave andagitated using a propeller-type agitator (temperature: 150° C., period:3 hours). The obtained mixture was further processed on a high-pressurehomogenizer (pressure: 100 kg/cm²) and then cooled to 25° C.

The cumulative volume-average particle size of the obtained slippingproperty imparting agent (B) was 10,000 nm. Copolymer  20.00 parts bymass (Ethylene/acrylic acid = 80/20 [mol percent]) Ammonia water (25mass percent)  1.09 parts by mass Water  78.91 parts by mass Total100.00 parts by mass

Production Example 3

All of the following constituents were placed in an autoclave andagitated using a propeller-type agitator (temperature: 140° C., period:3 hours). The obtained mixture was further processed on a high-pressurehomogenizer (pressure: 500 kg/cm²) and then cooled to 25° C.

The cumulative volume-average particle size of the obtained slippingproperty imparting agent (C) was 3,000 nm. Copolymer  40.00 parts bymass (Ethylene/potassium acrylate = 95/5 [mol percent]) Water  60.00parts by mass Total 100.00 parts by mass

Production Example 4

All of the following constituents were placed in an autoclave andagitated using a propeller-type agitator (temperature: 150° C., period:3 hours). The obtained mixture was further processed on a high-pressurehomogenizer (pressure: 700 kg/cm²) and then cooled to 25° C.

The cumulative volume-average particle size of the obtained slippingproperty imparting agent (D) was 15 nm. Copolymer  25.00 parts by mass(Ethylene/methacrylic acid = 90/10 [mol percent]) Sodium hydroxide  0.03part by mass Water  74.97 parts by mass Total 100.00 parts by mass

Production Example 5

All of the following constituents were placed in an autoclave andagitated using a propeller-type agitator (temperature: 140° C., period:3 hours). The obtained mixture was further processed on a high-pressurehomogenizer (pressure: 100 kg/cm²) and then cooled to 25° C.

The cumulative volume-average particle size of the obtained slippingproperty imparting agent (E) was 5,000 nm. Copolymer  60.00 parts bymass (Ethylene/methacrylic acid/methyl methacrylate = 75/10/15 [molpercent]) Potassium hydroxide  0.02 part by mass Water  39.98 parts bymass Total 100.00 parts by mass

Production Example 6

All of the following constituents were placed in an autoclave andagitated using a propeller-type agitator (temperature: 140° C., period:3 hours). The obtained mixture was slowly cooled to 25° C.

The cumulative volume-average particle size of the obtained slippingproperty imparting agent (F) was 45,000 nm. Copolymer  20.00 parts bymass (Styrene/maleic acid = 55/45 [mol percent]) Diethanolamine  0.004part by mass Water 79.996 parts by mass Total 100.00 parts by mass

Comparative Production Example 1

All of the following constituents were placed in an autoclave andagitated using a propeller-type agitator (temperature: 140° C., period:3 hours). The obtained mixture was further processed on a high-pressurehomogenizer (pressure: 1,000 kg/cm²) and then cooled to 25° C.

The cumulative volume-average particle size of the obtained slippingproperty imparting agent (G) was 40 nm. Copolymer  30.00 parts by mass(Ethylene/acrylic acid = 99.5/0.5 [mol percent]) Potassium hydroxide 0.002 part by mass Water 69.998 parts by mass Total 100.00 parts bymass

Comparative Production Example 2

All of the following constituents were placed in an autoclave andagitated using a propeller-type agitator (temperature: 140° C., period:3 hours). The obtained mixture was slowly cooled to 25° C.

The cumulative volume-average particle size of the obtained slippingproperty imparting agent (H) was 80,000 nm. Copolymer 50.000 parts bymass (Ethylene/methacrylic acid/methyl methacrylate = 40/35/25 [molpercent]) Sodium hydroxide  0.006 part by mass Water 49.994 parts bymass Total 100.00 parts by mass

Comparative Production Example 3

All of the following constituents were placed in an autoclave andagitated using a propeller-type agitator (temperature: 140° C., period:3 hours). The obtained mixture was further processed on a high-pressurehomogenizer (pressure: 200 kg/cm²) and then cooled to 25° C.

The cumulative volume-average particle size of the obtained slippingproperty imparting agent (I) was 5,000 nm. Copolymer  75.00 parts bymass (Ethylene/methacrylic acid = 90/10 [mol percent]) Ammonia water (25mass percent)  6.80 parts by mass Water  18.20 parts by mass Total100.00 parts by mass

Comparative Production Example 4

All of the following constituents were placed in an autoclave andagitated using a propeller-type agitator (temperature: 180° C., period:3 hours). The obtained mixture was further processed on a high-pressurehomogenizer (pressure: 700 kg/cm²) and then cooled to 25° C.

The cumulative volume-average particle size of the obtained slippingproperty imparting agent (J) was 30 nm. Oxidized polyethylene wax  32.0parts by mass (Acid value: 18 mgKOH/g) Potassium hydroxide  5.1 parts bymass Polyoxyethylene (added by 11  8.0 parts by mass mols) dodecyl alkylether Water  54.9 parts by mass Total 100.0 parts by mass

Comparative Production Example 5

All of the following constituents were placed in an autoclave andagitated using a propeller-type agitator (temperature: 180° C., period:3 hours). The obtained mixture was further processed on a high-pressurehomogenizer (pressure: 700 kg/cm²) and then cooled to 25° C.

The cumulative volume-average particle size of the obtained slippingproperty imparting agent (K) was 30 nm. Oxidized polyethylene wax  28.8parts by mass (Acid value: 18 mgKOH/g) Potassium hydroxide  4.6 parts bymass Polyoxyethylene (added by 11 mols)  7.2 parts by mass dodecyl alkylether SN Defoamer 171 (antifoamer  10.0 parts by mass manufactured bySAN NOPCO) Water  49.4 parts by mass Total 100.0 parts by mass

Comparative Production Example 6

All of the following constituents were placed in an autoclave andagitated using a propeller-type agitator (temperature: 180° C., period:3 hours). The obtained mixture was further processed on a high-pressurehomogenizer (pressure: 700 kg/cm²) and then cooled to 25° C.

The cumulative volume-average particle size of the obtained slippingproperty imparting agent (L) was 20 nm. Oxidized polyethylene wax  32.0parts by mass (Acid value: 18 mgKOH/g) Potassium hydroxide  4.6 parts bymass Polyoxyethylene (added by 4 mols)  4.0 parts by mass stearyl aminoether Polyoxyethylene (added by 11 mols)  8.0 parts by mass dodecylalkyl ether Water  51.4 parts by mass Total 100.0 parts by mass

The number-average molecular weights, cumulative volume-average particlesizes, neutralized salts and neutralization levels of the slippingproperty imparting agents obtained by Production Examples 1 through 6and Comparative Production Examples 1 through 6 are shown in Table 1.

[Measurement of Cumulative Volume-Average Particle Size]

The cumulative volume-average particle sizes of slipping propertyimparting agents were measured using a laser-diffraction typeparticle-size analyzer [Micro Track Particle-Size Analyzer, manufacturedby Nikkiso]. TABLE 1 Copolymer (I) Number- Unsaturated averageCumulative Alkali Slippage- Olefin (a) carboxylate (b) Monomer (c)molecular volume-average content [mol adding agent [mol %] [mol %] [mol%] Weight particle size [nm] Neutralized salt equivalent] Examples AEthylene Acrylic acid — 3000 60 Potassium 60 (90.0) (10.0) B EthyleneAcrylic acid — 700 10000 Ammonium 280 (80.0) (20.0) C Ethylene Acrylicacid — 48000 3000 Potassium 90 (95.0) (5.0) D Ethylene Methacrylic acid— 2500 15 Sodium 60 (90.0) (10.0) E Ethylene Methacrylic acid Methyl20000 5000 Potassium 100 (75.0) (10.0) methacrylate (15.0) F StyreneMaleic acid — 25000 45000 Diethanolamine 10 (55.0) (45.0) Comparative GEthylene Acrylic acid — 3000 40 Potassium 95 examples (99.5) (0.5) HEthylene Acrylic acid Methyl 70000 80000 Sodium 60 (40.0) (35.0)methacrylate (25.0) I Ethylene Methacrylic acid — 300 5000 Ammonium 400(90.0) (10.0) J Oxidized polyethylene 2000 30 Potassium 90 (acid value:18 mgKOH/g) K Oxidized polyethylene 2000 30 Potassium 90 (acid value: 18mgKOH/g), containing 10 mass % of antifoamer L Oxidized polyethylene2000 20 Potassium 90 (acid value: 18 mgKOH/g) polyoxyethylene stearylamino ether M Calcium stearate (NOPCOAT C-104-HS, — 5000 — —manufactured by SAN NOPCO)

Example 1

Twelve parts of softwood kraft pulp, 22 parts of thermo-mechanical pulpand 66 parts of deinked waste-paper pulp were mixed and then defiberizedby a refiner to prepare a pulp slurry (paper material) with a freenessof 110 ml (CSF/Canada Standard Freeness). The obtained pulp slurry wasmixed with a filler consisting of 2 percent of white carbon relative tothe absolute dry weight of pulp, and then processed on a twin-wirepapermaking machine to obtain a base newsprint paper with a basis weightof 42 g/m².

Next, the paper was coated with oxidized starch to a coating weight of0.5 g/m², and slipping property imparting agent A to a coating weight of0.0031 g/m² (per both sides), respectively, using a gate-roll coateroperated at a coating speed of 1,300 m/min, after which the coated paperwas calendered to obtain an offset newsprint paper.

Example 2

An offset newsprint paper was obtained under the same condition asdescribed in Example 1, except that slipping property imparting agent Awas applied to a coating weight of 0.0044 g/m² (per both sides).

Example 3

An offset newsprint paper was obtained under the same condition asdescribed in Example 1, except that slipping property imparting agent Dwas applied to a coating weight of 0.0035 g/m² (per both sides).

Example 4

An offset newsprint paper was obtained under the same condition asdescribed in Example 1, except that slipping property imparting agent Dwas applied to a coating weight of 0.0049 g/m² (per both sides).

Comparative Example 1

An offset newsprint paper was obtained under the same condition asdescribed in Example 1, except that slipping property imparting agentwas not applied.

Comparative Example 2

An offset newsprint paper was obtained under the same condition asdescribed in Example 1, except that slipping property imparting agent Jwas applied to a coating weight of 0.0045 g/m² (per both sides).

Comparative Example 3

An offset newsprint paper was obtained under the same condition asdescribed in Example 1, except that slipping property imparting agent Kwas applied to a coating weight of 0.0043 g/m² (per both sides).

Comparative Example 4

An offset newsprint paper was obtained under the same condition asdescribed in Example 1, except that slipping property imparting agent Lwas applied to a coating weight of 0.0044 g/m² (per both sides).

Example 5

An offset newsprint paper was obtained under the same condition asdescribed in Example 1, except that the starch was applied to a coatingweight of 0.3 g/m² (per both sides), slipping property imparting agent Ato 0.0050 g/m² (per both sides), and surface-sizing agent (KN-520,manufactured by Harima Chemicals) to 0.06 g/m² (per both sides),respectively.

Example 6

An offset newsprint paper was obtained under the same condition asdescribed in Example 5, except that slipping property imparting agent Awas applied to a coating weight of 0.0091 g/m² (per both sides).

Comparative Example 5

An offset newsprint paper was obtained under the same condition asdescribed in Example 5, except that slipping property imparting agentwas not applied.

The offset newspaper print papers obtained in Examples 1 through 6 andComparative Examples 1 through 5 were measured for the items specifiedbelow. The results are shown in Table 2.

Scum generation rate: Five kilograms of the coating solution was letstand for 4 hours, after which it was filtered through a 42-mesh wirenet and the absolute dry weight of filtered residue was measured. Thescum generation rate was obtained as the percentage of the measuredabsolute dry weight of filtered residue to the total weight of solidcontent in the coating solution.

Static friction coefficient and dynamic friction coefficient:Measurement was taken in accordance with JIS P 8147. In general,friction coefficients of less than 0.6 do not pose any problem foroffset newsprint papers.

Measurement of tackiness: Two pieces, each of 4×6 cm in size, were cutout from the offset newsprint paper. The cutout paper pieces were soakedin 20° C. waster for 5 seconds, and then adhered together with thecoated surfaces contacting each other. The adhered paper pieces weresandwiched between base newsprint papers, processed through rolls undera pressure of 50 kg/m², and then left in a temperature of 25° C. andrelative humidity of 60 percent for 24 hours to adjust the moisturecontent. Thereafter, a test piece of 3×6 cm in size was prepared fromthe processed paper sample, and the tackiness of the test piece wasmeasured on a tensile tester at a pulling speed of 30 mm/min. Ingeneral, the larger the measured value, the less likely the paperseparates (i.e., its adhesion is stronger).

For the offset newsprint papers obtained per the present invention,those showing a tackiness of 500 mN/3 cm or less were rated as offering“good separability.” TABLE 2 Scum Static Dynamic generation frictionfriction Tackiness rate (%) coefficient coefficient (mN/3 cm) Example 10 0.59 0.57 196 Example 2 0 0.57 0.55 147 Example 3 0 0.59 0.57 196Example 4 0 0.57 0.55 147 Example 5 0 0.56 0.51 400 Example 6 0 0.520.48 380 Comparative 0 0.60 0.58 343 example 1 Comparative 1.5 0.44 0.42147 example 2 Comparative 2.1 0.42 0.42 157 example 3 Comparative 1.80.43 0.42 137 example 4 Comparative 0 0.59 0.54 441 example 5

As shown in Table 2, the slipping property imparting agents for clearcoat as prepared per the present invention produced no scum, providedgood coatability, and exhibited no undesirable tackiness. On the otherhand, the slipping property imparting agents for clear coat as obtainedin Comparative Examples 2 through 4 produced scum and exhibited poorcoatability.

INDUSTRIAL FIELD OF APPLICATION

While the conventional slipping property imparting agents for clear coatproduce scum and exhibit poor coatability, the slipping propertyimparting agent for clear coat as proposed by the present inventionproduces no scum, offers good coatability, and exhibits no undesirabletackiness. The slipping property imparting agent for clear coat asproposed by the present invention manifests sufficient slippage and alsoadds a sizing property when coated on: recording papers such as PPCpaper, inkjet paper, laser printer paper, form paper, thermal transferpaper and thermo-sensitive recording paper; coated papers such as artpaper, cast coated paper and woodfree coated paper; packaging paperssuch as kraft paper and pure-white roll paper; other papers such asnotepad paper, paper for making books, printing paper and newsprintpaper; paperboards for making paper containers such as manila boardpaper, white paperboard and chip board paper; and other paperboards suchas liner.

1. A slipping property imparting agent for clear coat which comprises acopolymer whose constituents are unsaturated olefin (constituent (a))and unsaturated carboxylic acid (carboxylate) (constituent (b)).
 2. Theslipping property imparting agent as described in claim 1, wherein saidcopolymer contains 50 to 99 mol percent of constituent (a) and 50 to 1mol percent of constituent (b) to the total mol number of constituents(a) and (b) combined.
 3. The slipping property imparting agent asdescribed in claim 1, wherein said copolymer contains a constituent(constituent (c)) which can be copolymerized with the unsaturated olefin(constituent (a)) and the unsaturated carboxylic acid (carboxylate)(constituent (b)), by up to 20 mol percent of the total mol number ofconstituents (a) and (b) combined.
 4. The slipping property impartingagent as described in claim 1, wherein said copolymer contains 0.05 to 3mol equivalent of alkalis per 1 mol equivalent of carboxyl groups. 5.The slipping property imparting agent as described in claim 1, wherein acumulative volume-average particle size of said copolymer is 1 to 50,000nm.
 6. A clear coated paper coated with 0.001 to 1 g/m² by solid contentof the slipping property imparting agent for clear coat as described inclaim
 1. 7. The slipping property imparting agent as described in claim2, wherein said copolymer contains a constituent (constituent (c)) whichcan be copolymerized with the unsaturated olefin (constituent (a)) andthe unsaturated carboxylic acid (carboxylate) (constituent (b)), by upto 20 mol percent of the total mol number of constituents (a) and (b)combined.
 8. The slipping property imparting agent as described in claim2, wherein said copolymer contains 0.05 to 3 mol equivalent of alkalisper 1 mol equivalent of carboxyl groups.
 9. The slipping propertyimparting agent as described in claim 3, wherein said copolymer contains0.05 to 3 mol equivalent of alkalis per 1 mol equivalent of carboxylgroups.
 10. The slipping property imparting agent as described in claim2, wherein a cumulative volume-average particle size of said copolymeris 1 to 50,000 nm.
 11. The slipping property imparting agent asdescribed in claim 3, wherein a cumulative volume-average particle sizeof said copolymer is 1 to 50,000 nm.
 12. The slipping property impartingagent as described in claim 4, wherein a cumulative volume-averageparticle size of said copolymer is 1 to 50,000 nm.